Thread: New lathe stand design

digging up your floor sounds like its a bit of an overkill
5 inches of concrete can withstand a lot of weight...assumes the base is good

Else why not put in a full chassis under the lathe but on top of your concrete, rather than dig it up.......

further, if you do dig it up, your pads are going to have to be wide and deep enough to stop movement/sagging anyway ( your in Perth eh Mark...isnt that built on sand)....a full length pad (your concrete floor) sounds as though it will be more stable

I'm with eskimo, I'd leave the concrete as it is or cut out one much larger section. You don't want each end of the lathe sitting on a seprate piece of concrete. I don't see how going to 400mm deep over such a small area will help.

Also what makes you think you cant use Dyna bolts in a 125mm slab?

Stuart

Another vote for Dyna bolts. It will be less likely to move if you attach it to the existing slab than 2 squares.
My mill manual like yours, recommends digging out a square 400-500mm deep and putting in hook thread rod, but it's doing just fine sitting on the slab.

If your stands are like mine they do the job well enough, but the storage is awkward to get to.
It always good to have storage and tools at hand when your working on the lathe. I have seen some designs where the have draws with heavy duty runners supporting them for tool holders etc directly under the swarf tray.


Dave

Digging the floor up will be a very simple operation with the tools I have for the task. The floor is probably 40 years old and I am concerned about the possibility of the pad having settled under the slab. I live about 300km from Perth - the ground around here is gravel/rock, but the floor is built on a sand pad about 60cm above ground level, which is retained by brick walls.

Given my concerns about subsiding of the pad under the slab, and member's replies, a monolithic footing sounds like the go. I would shape the walls of the footing to end up like a pyramid with its top cut off - wide base with a flat top. My inspiration - if you could call it that - to go 400mm deep was the mounting detail suggested for my HM-52G mill, as Dave mentions. I thought that a heavier mass would be preferred over a smaller mass - which obviously suggests a monolithic footing with a fair bit of steel in it tying it all together. Why didnt I see that earlier?

Storage under the lathe isnt a major concern as I have a mobile tool/parts trolley that I use, plus a storage cupboard and shelving unit is only two steps away from the head. I like the idea of a draw slung under the tray though - you can never have too much storage!

Thoughts about the revised plan - single deep footing, with tie down bolts set into concrete?

I had my lathe bolted down for around 4-5 tears before moving it. It is now just siting where it is now on adjustable feet (because I don't want to drill holes where it is temporally) and has been fine. My concrete has been down 30-35 years and is still as strong as the day it was laid. When I build my new shed it will be bolted down again to the new floor.
Their is not going to be much pull on 6 to 8 dyna bolts on your concrete floor. If in doubt drill a 10mm one in 50-60mm and attach a long scrap angle or something laying around and try to pulling it out. Their are always chemical fasteners as well which do a great job.
It's up to you it's you time and money, but if this was a 2 to 10 ton lathe I would be looking at doing it, but its only a 4-500 kg home hobby lathe so it probably wont benefit at all by doing.
With the storage under the lathe, if you could pick up some cheap tool boxes with draws and make the stand frame to go around them to suit.

Dave

The problem I see with a cutting a hole in a slab on a sand pad, is not weakening the floor around the hole. If you just want to add mass(which I think is more important for a mill than a lathe) you could build two frames like the one you have drawn for the headstock and fill them with concrete.

Think about how much your car weighs. There is a good chance it has about the weight of your lathe on each tire.

If the floor is still in good repair after 40 years, isn't that a good sign?

Stuart

You bring up a good point their Stuart about weakening the floor around it. I will be hard to stop the sand running out from under it into the hole leaving it hollow.
On another forum their were guys talking about building a concrete stand for their lathe and a few already had them. I also saw a concrete stand made up for a bench top mill, which looked quite good.

Dave

In my best Spike Milligan voice impersonation....Overkillll! And a lot of work for no real benefit.

thinking about this some more...instead of digging your perfectly good floor, make a 1 piece concrete plinth and lay it on top of your existing concrete...but it shouldnt be necessary

instead of digging your perfectly good floor

Remember I have already expressed concern over the likelihood of subsidence of the pad under the concrete.
Regardless of this, I am shelving plans to cut through the floor. I will construct my new stand, level it on the existing slab, and then tie it down with Dyna bolts. If the finish of the lathe turns out to be below par, once properly set up, I can always put in a new footing/pad at a later date. If I have to do that you will all be hearing about it!

Keep us up to date with your new plans.
My perfect stand would be one with an easy removed swarf tray and a heap of heavy duty draws from shallow to deep ones at the bottom for chucks etc.

Dave